The HRH1 Knockout SK-HEP-1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population in which the HRH1 gene, encoding the histamine H1 receptor, has been disrupted to generate a loss-of-function model. This product provides a heterogeneous pool of human SK-HEP-1 cells with targeted HRH1 inactivation, enabling functional studies of histamine-mediated signaling without the confounding presence of wild-type receptor activity. The polyclonal format preserves genetic diversity inherent to the CRISPR/Cas9-edited population, making it suitable for experiments where uniform knockout efficiency is not required and clonal effects are minimal.
The parental SK-HEP-1 line is a human liver adenocarcinoma-derived cell line that displays endothelial-like characteristics, widely adopted as a model for liver sinusoidal endothelial cells. These cells recapitulate key facets of hepatic endothelial biology, including barrier function, angiogenic responses, and interactions with circulating immune cells and tumor cells. Their unique origin combines hepatic and endothelial features, offering a versatile platform for investigating liver-specific vascular processes, angiogenesis, and metastatic colonization in the hepatic microenvironment.
HRH1 encodes the histamine H1 receptor, a Gq/11-coupled GPCR that transduces extracellular histamine signals into intracellular cascades. Upon ligand binding, the receptor activates phospholipase C (PLC) via Gq/11, generating inositol trisphosphate (IP3) and diacylglycerol. IP3 triggers calcium mobilization from intracellular stores, while calcium and diacylglycerol activate protein kinase C (PKC) and downstream mitogen-activated protein kinases (MAPKs) including ERK, JNK, and p38. These events culminate in transcription factor activation, notably NF-??B, driving pro-inflammatory gene expression. HRH1 function is modulated by upstream inputs such as mast cell degranulation and IgE receptor crosslinking, and involves interaction partners including ??-arrestin and scaffold proteins that fine-tune signal duration and magnitude.
In the SK-HEP-1 background, HRH1 knockout disrupts histamine-induced signaling pathways that are central to endothelial permeability, leukocyte adhesion, and angiogenic switch. This model is thus invaluable for dissecting how endothelial histamine reception contributes to hepatic inflammation, sinusoidal barrier regulation, and the vascular niche supporting tumor metastasis. It allows researchers to isolate H1-specific effects from other histamine receptor subtypes and endogenous signaling crosstalk, providing a clean background for mechanistic studies and therapeutic target validation in a liver endothelial context.
Research applications span allergy and inflammation research, GPCR pharmacology, antihistamine screening, and hepatic vascular biology. Typical assays include calcium flux measurements to assess receptor-mediated calcium release, NFAT/NF-??B reporter assays for transcriptional readouts, western blotting for phospho-ERK and phospho-p38, RT-qPCR for inflammatory cytokines such as IL-6 and IL-8, and cell migration assays to evaluate angiogenic and metastatic behaviors. Flow cytometry for surface HRH1 expression confirms knockout, while co-immunoprecipitation can explore interactions with Gq/11 or ??-arrestin. Vascular permeability assays in transwell systems further probe endothelial barrier function. For further information, please contact Ascent Research.
